U.S. Pat. No. 4,187,033 discloses a rack and pinion power steering assembly. The rack and pinion power steering assembly comprises an elongate rack and a pair of tie rods. The rack is moved longitudinally in a power steering gear housing, and has opposite ends extending out of the power steering gear housing. Each of the tie rods has threads at one end and a ball at the other end. The threaded ends of the tie rods are connected to respective steerable vehicle wheels. The balls at the other ends of the tie rods are connected to opposite ends of the rack by respective joints. The joints thus connect the tie rods and the rack for longitudinal movement together to effect steering movement of the steerable vehicle wheels in response to longitudinal movement of the rack.
Each joint disclosed in the '033 patent comprises a tubular housing. The housing has coaxial first and second open ends. A chamber is defined in the housing adjacent to the first open end, and a passage extends axially inward from the second open end. The ball end of a tie rod is received in the chamber, with the tie rod extending out through the first open end of the housing. An end portion of the rack extends into the passage in the housing through the second open end, and has external threads engaged with internal threads in the housing.
The ball end of the tie rod is supported for pivotal movement in the chamber relative to the housing, and the tie rod is thus movable pivotally relative to the rack. However, forces applied to the joint during longitudinal movement of the rack and the tie rod are directed primarily in an axial direction through the joint. Such forces, if large enough, can pull the ball end of the tie rod in an axial direction out of the first open end of the tubular housing.